Operating cycles, in which no combustion occurs, are termed as misfired cycles. Internal combustion engines may suffer from misfire for various reasons. Misfire can be caused by a malfunction of the ignition system. Alternatively, the mixture of fuel and air may be inappropriate, for example, due to insufficient fuel feed or an excess of fuel in the fuel air mixture. As an undesired consequence of misfire, unburnt fuel may build up in the exhaust passages of the internal combustion engine. This can lead to explosions and potential damage to the engine.
An exemplary system for monitoring an ignition system is disclosed in DE 10 2008 041 386 A1. A controller has a current detection mechanism for detecting secondary current flowing between electrodes of an ignition plug in a condition in which ignition voltage is provided between the electrodes. An ignition detection mechanism detects a sequence of ignition if the secondary current detected by the current detection mechanism is equal to or larger than a preset reference current value, continues for a preset reference time, and detects malfunctioning of the ignition if the duration of the detection is smaller than the reference time.
The present disclosure is directed, at least in part, to improving or overcoming one or more aspects of prior systems.